Recently, there are household electric devices that execute a cooperative process within a user's home. Such household electric devices, through the execution of a cooperative process, offer a sense of increased convenience to users. In one example of a cooperative process, a DVD (Digital Versatile Disc) player performs disc playback and a television broadcast receiver performs switching between different video input sources.
In the above-described cooperative process, the DVD player first receives a disc playback instruction from a user. Then, the DVD players commences disc playback and outputs, to the television broadcast receiver, video images obtained through disc playback and an AV/C (Audio Video Control) command, which urges the television broadcast receiver to use external input as the video input source (Non-Patent Literature 1). Upon receiving the AV/C command, the television broadcast receiver switches to using external input that is connected with the DVD player as the video input source, and displays video images output from the DVD player on a display.
The DVD player and the television broadcast receiver executing the cooperative process as described above allows the user to enjoy video images played back by the DVD player on the television broadcast receiver without having to perform any user operation for controlling the television broadcast receiver. Meanwhile, it should be noted that in the above-described example, the DVD player and the television broadcast receiver need to be programmed in advance to execute the cooperative process.